// component/singnature.js
let canvas = null;
let canvasContext = null;
let canvasSize = {
	width: 0,
	height: 0,
}

Component({

	/**
	 * 组件的属性列表
	 */
	properties: {
		// Text color
		lineColor: {
			type: String,
			value: '#1A1A1A', // 颜色                                                                         
		}
	},

	/**
	 * 组件的初始数据
	 */
	data: {
		transparent: 1, // 透明度
		selectColor: 'black',
		lineSize: 1.2, // 笔记倍数
		lineMin: 0.5, // 最小笔画半径
		lineMax: 4, // 最大笔画半径
		pressure: 1.2, // 默认压力
		smoothness: 60, //顺滑度，用60的距离来计算速度
		currentPoint: {},
		currentLine: [], // 当前线条
		firstTouch: true, // 第一次触发
		radius: 1, //画圆的半径
		cutArea: {
			top: 0,
			right: 0,
			bottom: 0,
			left: 0
		}, //裁剪区域
		bethelPoint: [], //保存所有线条 生成的贝塞尔点；
		lastPoint: 0,
		chirography: [], //笔迹
		currentChirography: {}, //当前笔迹
		linePrack: [] //划线轨迹 , 生成线条的实际点
	},
	lifetimes:{
		ready(){
			this.getCanvasAndContext();
		},
	},
	/**
	 * 组件的方法列表
	 */
	methods: {
		/* 创建 canvas 画布 上下文 */
		getCanvasAndContext() {
			let that = this;
			let queryDom = wx.createSelectorQuery().in(this).select("#signatureComponentCanvas");
			queryDom.fields({
				node: true,
				size: true
			}).exec((res) => {
				canvas = res[0].node;
				canvasContext = canvas.getContext("2d");

				const dpr = wx.getSystemInfoSync().pixelRatio
				canvas.width = res[0].width * dpr;
				canvas.height = res[0].height * dpr;
				canvasContext.scale(dpr, dpr)
				canvasSize = {
					width:canvas.width,
					height:canvas.height
				}
				that.setCanvasBg('#FFFFFF');

			});
		},

		/*======所有自定义函数======*/

		// 笔迹开始
		uploadScaleStart(e) {
			if (e.type != 'touchstart') return false;
			canvasContext.fillStyle = this.data.lineColor; // 初始线条设置颜色
			canvasContext.globalAlpha = this.data.transparent; // 设置半透明
			let currentPoint = {
				x: e.touches[0].x,
				y: e.touches[0].y
			}
			let currentLine = this.data.currentLine;
			currentLine.unshift({
				time: new Date().getTime(),
				dis: 0,
				x: currentPoint.x,
				y: currentPoint.y
			})
			this.setData({
				currentPoint,
				// currentLine
			})
			if (this.data.firstTouch) {
				this.setData({
					cutArea: {
						top: currentPoint.y,
						right: currentPoint.x,
						bottom: currentPoint.y,
						left: currentPoint.x
					},
					firstTouch: false
				})
			}
			this.pointToLine(currentLine);
		},
		// 笔迹移动
		uploadScaleMove(e) {
			if (e.type != 'touchmove') return false;
			if (e.cancelable) {
				// 判断默认行为是否已经被禁用
				if (!e.defaultPrevented) {
					e.preventDefault();
				}
			}
			let point = {
				x: e.touches[0].x,
				y: e.touches[0].y
			}

			//测试裁剪
			if (point.y < this.data.cutArea.top) {
				this.data.cutArea.top = point.y;
			}
			if (point.y < 0) this.data.cutArea.top = 0;

			if (point.x > this.data.cutArea.right) {
				this.data.cutArea.right = point.x;
			}
			if (canvasSize.width - point.x <= 0) {
				this.data.cutArea.right = canvasSize.width;
			}
			if (point.y > this.data.cutArea.bottom) {
				this.data.cutArea.bottom = point.y;
			}
			if (canvasSize.height - point.y <= 0) {
				this.data.cutArea.bottom = canvasSize.height;
			}
			if (point.x < this.data.cutArea.left) {
				this.data.cutArea.left = point.x;
			}
			if (point.x < 0) this.data.cutArea.left = 0;

			this.setData({
				lastPoint: this.data.currentPoint,
				currentPoint: point
			})
			let currentLine = this.data.currentLine
			currentLine.unshift({
				time: new Date().getTime(),
				dis: this.distance(this.data.currentPoint, this.data.lastPoint),
				x: point.x,
				y: point.y
			})
			// this.setData({
			//   currentLine
			// })
			this.pointToLine(currentLine);
		},
		// 笔迹结束
		uploadScaleEnd(e) {
			if (e.type != 'touchend') return 0;
			let point = {
				x: e.changedTouches[0].x,
				y: e.changedTouches[0].y
			}
			this.setData({
				lastPoint: this.data.currentPoint,
				currentPoint: point
			})
			let currentLine = this.data.currentLine
			currentLine.unshift({
				time: new Date().getTime(),
				dis: this.distance(this.data.currentPoint, this.data.lastPoint),
				x: point.x,
				y: point.y
			})
			// this.setData({
			//   currentLine
			// })
			if (currentLine.length > 2) {
				var info = (currentLine[0].time - currentLine[currentLine.length - 1].time) / currentLine.length;
				//$("#info").text(info.toFixed(2));
			}
			//一笔结束，保存笔迹的坐标点，清空，当前笔迹
			//增加判断是否在手写区域；
			this.pointToLine(currentLine);
			var currentChirography = {
				lineSize: this.data.lineSize,
				lineColor: this.data.lineColor
			};
			var chirography = this.data.chirography
			chirography.unshift(currentChirography);
			this.setData({
				chirography
			})
			var linePrack = this.data.linePrack
			linePrack.unshift(this.data.currentLine);
			this.setData({
				linePrack,
				currentLine: []
			})
		},

		//画两点之间的线条；参数为:line，会绘制最近的开始的两个点；
		pointToLine(line) {
			this.calcBethelLine(line);
			return;
		},
		//计算插值的方式；
		calcBethelLine(line) {
			if (line.length <= 1) {
				line[0].r = this.data.radius;
				return;
			}
			let x0, x1, x2, y0, y1, y2, r0, r1, r2, len, lastRadius, dis = 0,
				time = 0,
				curveValue = 0.5;
			if (line.length <= 2) {
				x0 = line[1].x
				y0 = line[1].y
				x2 = line[1].x + (line[0].x - line[1].x) * curveValue;
				y2 = line[1].y + (line[0].y - line[1].y) * curveValue;
				//x2 = line[1].x;
				//y2 = line[1].y;
				x1 = x0 + (x2 - x0) * curveValue;
				y1 = y0 + (y2 - y0) * curveValue;;

			} else {
				x0 = line[2].x + (line[1].x - line[2].x) * curveValue;
				y0 = line[2].y + (line[1].y - line[2].y) * curveValue;
				x1 = line[1].x;
				y1 = line[1].y;
				x2 = x1 + (line[0].x - x1) * curveValue;
				y2 = y1 + (line[0].y - y1) * curveValue;
			}
			//从计算公式看，三个点分别是(x0,y0),(x1,y1),(x2,y2) ；(x1,y1)这个是控制点，控制点不会落在曲线上；实际上，这个点还会手写获取的实际点，却落在曲线上
			len = this.distance({
				x: x2,
				y: y2
			}, {
				x: x0,
				y: y0
			});
			lastRadius = this.data.radius;
			for (let n = 0; n < line.length - 1; n++) {
				dis += line[n].dis;
				time += line[n].time - line[n + 1].time;
				if (dis > this.data.smoothness) break;
			}
			this.setData({
				radius: Math.min(time / len * this.data.pressure + this.data.lineMin, this.data.lineMax) * this.data.lineSize
			});
			line[0].r = this.data.radius;
			//计算笔迹半径；
			if (line.length <= 2) {
				r0 = (lastRadius + this.data.radius) / 2;
				r1 = r0;
				r2 = r1;
				//return;
			} else {
				r0 = (line[2].r + line[1].r) / 2;
				r1 = line[1].r;
				r2 = (line[1].r + line[0].r) / 2;
			}
			let n = 5;
			let point = [];
			for (let i = 0; i < n; i++) {
				let t = i / (n - 1);
				let x = (1 - t) * (1 - t) * x0 + 2 * t * (1 - t) * x1 + t * t * x2;
				let y = (1 - t) * (1 - t) * y0 + 2 * t * (1 - t) * y1 + t * t * y2;
				let r = lastRadius + (this.data.radius - lastRadius) / n * i;
				point.push({
					x: x,
					y: y,
					r: r
				});
				if (point.length == 3) {
					let a = this.ctaCalc(point[0].x, point[0].y, point[0].r, point[1].x, point[1].y, point[1].r, point[2].x, point[2].y, point[2].r);
					a[0].color = this.data.lineColor;
					// let bethelPoint = this.data.bethelPoint;
					// console.log(a)
					// console.log(this.data.bethelPoint)
					// bethelPoint = bethelPoint.push(a);
					this.bethelDraw(a, 1);
					point = [{
						x: x,
						y: y,
						r: r
					}];
				}
			}
			this.setData({
				currentLine: line
			})
		},
		//求两点之间距离
		distance(a, b) {
			let x = b.x - a.x;
			let y = b.y - a.y;
			return Math.sqrt(x * x + y * y);
		},
		ctaCalc(x0, y0, r0, x1, y1, r1, x2, y2, r2) {
			let a = [],
				vx01, vy01, norm, n_x0, n_y0, vx21, vy21, n_x2, n_y2;
			vx01 = x1 - x0;
			vy01 = y1 - y0;
			norm = Math.sqrt(vx01 * vx01 + vy01 * vy01 + 0.0001) * 2;
			vx01 = vx01 / norm * r0;
			vy01 = vy01 / norm * r0;
			n_x0 = vy01;
			n_y0 = -vx01;
			vx21 = x1 - x2;
			vy21 = y1 - y2;
			norm = Math.sqrt(vx21 * vx21 + vy21 * vy21 + 0.0001) * 2;
			vx21 = vx21 / norm * r2;
			vy21 = vy21 / norm * r2;
			n_x2 = -vy21;
			n_y2 = vx21;
			a.push({
				mx: x0 + n_x0,
				my: y0 + n_y0,
				color: "#1A1A1A"
			});
			a.push({
				c1x: x1 + n_x0,
				c1y: y1 + n_y0,
				c2x: x1 + n_x2,
				c2y: y1 + n_y2,
				ex: x2 + n_x2,
				ey: y2 + n_y2
			});
			a.push({
				c1x: x2 + n_x2 - vx21,
				c1y: y2 + n_y2 - vy21,
				c2x: x2 - n_x2 - vx21,
				c2y: y2 - n_y2 - vy21,
				ex: x2 - n_x2,
				ey: y2 - n_y2
			});
			a.push({
				c1x: x1 - n_x2,
				c1y: y1 - n_y2,
				c2x: x1 - n_x0,
				c2y: y1 - n_y0,
				ex: x0 - n_x0,
				ey: y0 - n_y0
			});
			a.push({
				c1x: x0 - n_x0 - vx01,
				c1y: y0 - n_y0 - vy01,
				c2x: x0 + n_x0 - vx01,
				c2y: y0 + n_y0 - vy01,
				ex: x0 + n_x0,
				ey: y0 + n_y0
			});
			a[0].mx = a[0].mx.toFixed(1);
			a[0].mx = parseFloat(a[0].mx);
			a[0].my = a[0].my.toFixed(1);
			a[0].my = parseFloat(a[0].my);
			for (let i = 1; i < a.length; i++) {
				a[i].c1x = a[i].c1x.toFixed(1);
				a[i].c1x = parseFloat(a[i].c1x);
				a[i].c1y = a[i].c1y.toFixed(1);
				a[i].c1y = parseFloat(a[i].c1y);
				a[i].c2x = a[i].c2x.toFixed(1);
				a[i].c2x = parseFloat(a[i].c2x);
				a[i].c2y = a[i].c2y.toFixed(1);
				a[i].c2y = parseFloat(a[i].c2y);
				a[i].ex = a[i].ex.toFixed(1);
				a[i].ex = parseFloat(a[i].ex);
				a[i].ey = a[i].ey.toFixed(1);
				a[i].ey = parseFloat(a[i].ey);
			}
			return a;
		},
		bethelDraw(point, is_fill, color) {
			canvasContext.beginPath();
			canvasContext.moveTo(point[0].mx, point[0].my);
			if (undefined != color) {
				canvasContext.fillStyle = color;
				canvasContext.strokeStyle = color;
			} else {
				canvasContext.fillStyle = point[0].color;
				canvasContext.strokeStyle = point[0].color;
			}
			for (let i = 1; i < point.length; i++) {
				canvasContext.bezierCurveTo(point[i].c1x, point[i].c1y, point[i].c2x, point[i].c2y, point[i].ex, point[i].ey);
			}
			canvasContext.stroke();
			if (undefined != is_fill) {
				canvasContext.fill(); //填充图形 ( 后绘制的图形会覆盖前面的图形, 绘制时注意先后顺序 )
			}
			// canvasContext.draw(true)
		},
		/*  
		*	设置canvas背景色  不设置  导出的canvas的背景为透明 
		*	@params：字符串  color
		*/
		setCanvasBg(color) {
			//rect() 参数说明  矩形路径左上角的横坐标，左上角的纵坐标, 矩形路径的宽度, 矩形路径的高度
			//这里是 canvasHeight - 4 是因为下边盖住边框了，所以手动减了写
			canvasContext.rect(0, 0, canvasSize.width, canvasSize.height- 4);
			canvasContext.fillStyle = color
			canvasContext.fill() //设置填充
		},


		/* 重置 画布 */
		resetDraw() {
			canvasContext.clearRect(0, 0, 700, 730);
			//设置canvas背景
			this.setCanvasBg("#FFFFFF");
		},

		async getCanvasToImageTempPath() {
			return await wx.canvasToTempFilePath({
				canvas: canvas,
			}, this).then(res => {
				return res.tempFilePath;
			}).catch(()=>{
				wx.showToast({
					title: '获取图片失败，请重试',
				})
			})
		},
		/* 预览签名图片 */
		async previewSingnatureImage() {
			let res = await this.getCanvasToImageTempPath();
			wx.previewImage({
				urls: [res], //预览图片 数组
			})
		},
		/* 保存签名图片至相册 */
		async saveSingnatureAsImage() {
			let tempPath = await this.getCanvasToImageTempPath();
			wx.saveImageToPhotosAlbum({
				filePath: tempPath,
				success(res) {
					wx.showToast({
						title: '已保存到相册',
						duration: 2000
					});
				}
			})
		},

	
		/*======所有自定义函数=END=====*/
	}
})